41. N581 chelates the divalent magnesium cation associated with ATP to help orient the molecule for optimal substitution. 42. Aromatic hydroxyaldehydes to divalent phenols ( Dakin reaction ) and gives under suitable conditions the corresponding benzoic acids. 43. Nanofilters can soften water by retaining scale-forming, hydrated divalent ions ( e . g. 44. The divalent calcium in lime acts as a cross-linking agent for protein and polysaccharide acidic side chains. 45. The light and heavy chains of Factor Va are linked via a divalent metal ion, such as calcium. 46. Divalent iron ( Fe ) and magnesium ( Mg ) readily substitute for the manganese in the crystal structure.47. Ferrochelatase is the best known member of a family of enzymes that add divalent metal cations to tetrapyrrole structures. 48. Sm is a typical and well studied metal due to its unusual stability in a divalent and trivalent state. 49. Divalent metal ions, especially artificially designed structures used in DNA nanotechnology, such as the double crossover motif.50. Activity greatly depends on the presence of a divalent copper ion and a reductant such as gallate or ascorbate.
